/*
 Copyright  2002-2004 MySQL AB, 2008 Sun Microsystems
 All rights reserved. Use is subject to license terms.

  The MySQL Connector/J is licensed under the terms of the GPL,
  like most MySQL Connectors. There are special exceptions to the
  terms and conditions of the GPL as it is applied to this software,
  see the FLOSS License Exception available on mysql.com.

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; version 2 of the
  License.

  This program is distributed in the hope that it will be useful,  
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  02110-1301 USA



 */
package com.mysql.jdbc;

import java.rmi.server.UID;
import java.sql.SQLException;
import java.sql.Savepoint;

/**
 * Represents SQL SAVEPOINTS in MySQL.
 * 
 * @author Mark Matthews
 * 
 * @version $Id$
 */
public class MysqlSavepoint implements Savepoint {
	private static String getUniqueId() {
		// no need to re-invent the wheel here...
		String uidStr = new UID().toString();

		int uidLength = uidStr.length();

		StringBuffer safeString = new StringBuffer(uidLength);

		for (int i = 0; i < uidLength; i++) {
			char c = uidStr.charAt(i);

			if (Character.isLetter(c) || Character.isDigit(c)) {
				safeString.append(c);
			} else {
				safeString.append('_');
			}
		}

		return safeString.toString();
	}

	private String savepointName;
	
	private ExceptionInterceptor exceptionInterceptor;

	/**
	 * Creates an unnamed savepoint.
	 * 
	 * @param conn
	 * 
	 * @throws SQLException
	 *             if an error occurs
	 */
	MysqlSavepoint(ExceptionInterceptor exceptionInterceptor) throws SQLException {
		this(getUniqueId(), exceptionInterceptor);
	}

	/**
	 * Creates a named savepoint
	 * 
	 * @param name
	 *            the name of the savepoint.
	 * 
	 * @throws SQLException
	 *             if name == null or is empty.
	 */
	MysqlSavepoint(String name, ExceptionInterceptor exceptionInterceptor) throws SQLException {
		if (name == null || name.length() == 0) {
			throw SQLError.createSQLException("Savepoint name can not be NULL or empty",
					SQLError.SQL_STATE_ILLEGAL_ARGUMENT, exceptionInterceptor);
		}

		this.savepointName = name;
		
		this.exceptionInterceptor = exceptionInterceptor;
	}

	/**
	 * @see java.sql.Savepoint#getSavepointId()
	 */
	public int getSavepointId() throws SQLException {
		throw SQLError.createSQLException("Only named savepoints are supported.",
				SQLError.SQL_STATE_DRIVER_NOT_CAPABLE, exceptionInterceptor);
	}

	/**
	 * @see java.sql.Savepoint#getSavepointName()
	 */
	public String getSavepointName() throws SQLException {
		return this.savepointName;
	}
}
